From DE 103 12 347 A1 there is already known a differential assembly with an intermediate shaft and a controllable coupling unit for the rear axle of a motor vehicle, constituting the main driving axle.
U.S. Publication No. 2006/0211532 A1 proposes a drive assembly with a gearbox, coupling and differential for a front axle. The assembly comprises an intermediate shaft which is also known as a link shaft and which, in respect of drive, connects the differential drive to a sideshaft. For locking the differential effect between the two sideshafts, there is provided a controllable coupling whose inner plate carrier is connected to the intermediate shaft in a rotationally fixed way and whose outer plate carrier is connected to the differential carrier in a rotationally fixed way. The coupling cage is supported in a rotationally fixed way in a coupling housing which is firmly attached to the differential housing. For actuating the multi-plate coupling, there is provided an actuator in the form of a ball ramp assembly which is controlled by an electric motor flanged to the coupling housing. The electric motor is controlled by an electronic control unit (ECU).
From U.S. Pat. No. 5,083,986 there is known a controllable coupling assembly with a pilot coupling, a main coupling, an electro-magnet, an anchor disc and a ramp mechanism. By actuating the electromagnet, there is attracted the anchor disc, so that the pilot coupling is loaded in the sense of being closed. As a result, the two ramp discs are rotated relative to one another and spread, as a result of which the main coupling is loaded in the sense of being closed. By way of example, there are proposed several applications for the coupling assembly, i.e. as a lock in a central differential, as an axle differential or a transfer box or a so-called hang-on coupling between a propeller shaft and a rear axle differential.
U.S. Pat. No. 6,109,408 proposes a similar electro-magnetically controllable coupling assembly with a pilot coupling and a main coupling. It shows different embodiments for the coupling assembly inside a propeller shaft of a motor vehicle. By closing the coupling, the rear axle is coupled to the driveline, which is also known as the “hang-on” or “on demand” concept. Inside a stationary receiving part for the magnetic coil, the coupling hub is rotatably supported, with the receiving part being connected to the vehicle body and housing of the rear axle differential.
From U.S. Publication No. 2005/0026732 A1 there is known a drive assembly with an intermediate shaft and a coupling unit. The coupling unit comprises a coupling cage which, in respect of drive, is connected to the differential carrier of the axle differential. The coupling unit is arranged in a two-part coupling housing which is flanged to the gearbox housing. In the coupling housing, there is provided an axial through-aperture towards the gearbox housing to allow the passage of a lubricant.
Because the available installation space is small, integrating active locking systems into the main driving axle of a motor vehicle is often complicated. In addition, existing components to be connected to the locking systems may have to be redesigned at additional expense, as a result of which the number of variants and thus costs are increased.